Fob boilers



2 Sheets-Sheet 1.

QM .R Km UR m NG m VP m A S (No Model.)

No. 504,896. Patented Sept. 1 2, 18931.

2 Sheets-Sheet 2.

(Nb Model.)

0. E. VAN AUKEN. SAFETY PLUG FOR BOILERS.

' v Patented Sept. 12, 1893 UNITED STATES PATENT OFFICE.

CLARENCE E VAN AUKEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHARLES P.MONASH.

SAFETY-PLUG FOR BOILERS.

SPECIFICATION forming part of Letters Patent No. 504,896, datedSeptember 12, 1893.

Application filed February 29, 1892. Serial No. 423,312. (No model.)

To all whom it may concern:

Beit known thatI,OLARENQEEVANAUKEN,

residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Safety-Plugs forBoilers, of which the following, in connection with the drawingsaccompanying and forming a part hereof, is a full and completedescription, sufficient to enable those skilled in the art to understandand use the same.

' My invention relates to that class of safety plugs which are placed onboilers in such manner that when the water in the boiler has fallenbelow a determined level, steam will escape from the boiler through thesafety plug, and thereby give warning of low water in theboiler. Thisdeviceis ordinarily called a low water alarm.

The objects of my invention are to obtain a safety plug wherein,whenwater in the boiler has fallen below a determined level, warning shallbe given in the usual manner by the escape of steam therefrom; to obtaina device, which when properly set cannot readily be changed or tamperedwith by any person; to obtain a device which cannot be by an ordinarilyintelligent person wrongfully or improperly set; to obtain a device,which shall by-its appearance indicate in a manner readily observablewhether or not the same is properly set for the escape of steamtherethrough upon the falling of the water in the boiler below thedetermined level; and to obtain a device which shall not be readilygetten out of order, and when gotten out of order,

its condition will be indicated in an easily observable manner to thoseskilled in the use thereof.

In safety plugs of this class a fusible plug is employed, such fusibleplugbeing of metal not fused by hot water but fusible by steam at agiven and determined temperature; and I attain these several objects byconstructing a device wherein the fusible plug used in conto be broughtagainst the valve stem so as to prevent the closing of the valve, suchstop be ing so brought into position to prevent the closing of the valveby the proper placing of the fusible plug in the casing.

As is hereinafter shown by one of the figures of the drawings thefusible plug may itself be interposed as a stop to prevent the closingof the valve, but such fusible plug being ordinarily of a metal notsufficiently hard to form a perfect stop, I prefer and do construct mydevice with a stop of material other than the fusible plug material.

I have illustrated my invention by the drawings accompanying and forminga part hereof in which- Figure 1, is a front elevation of the safetyplug embodying my invention; Fig. 2, a top plan view thereof; Fig. 3, atop plan view with a portion of the casing removed therefrom; Fig. 4:, avertical sectional view of the device and of a portion of a boiler towhich the same is attached, and showing the mannor of attachment. Fig.5, is a vertical sectional view of a modification of the constructionillustrated in Figs. 1 to 4., both inclusive, embodying my invention;and Fig. 6, a modification of the constructions illustrated in Fig. 5;embodying nearly all of the essential features of my invention.

The same letter of reference is used to indicate a given part where morethan one view thereof is shown in the several figures of the drawings.

A, is the shell of the boiler, a portion of which is illustrated.

B, is water contained in the boiler; b, the water line thereof.

C, is a tube extending from the shell of the boiler, in which shell itis secured, downward to a determined level of the water at or aboutwhich, an alarm is to be given by the device. C, is the lower end ofsuch tube or flue C.

C C are screw threads on tube or flue C.

D, is the principal shell or casing of the device, and the device is attimes attached to a boiler by extending the tube C through the shell ofthe boiler and turning threads D in the shell or case D downward uponthe screw threads of the tube C, a sufficient distance to hold suchshell or caseAfirmly thereon. The

. tube 0 may extend outward from the boiler so that the shell D formingtheprincipal portion of the casing shall not be in-con-tact with theshell of the boiler, if desired, and ordinarily such tube 0 does soextend, but in any event such tube 0 forms no part of my invent-ion.

The shell or case D is hollow, and d, is a.

6 is a screw thread on the outside of plug E, fitting into correspondingscrew threads in the shell or casing D and it is by turning the plug Ethat, by means of the screw threads 6 such plug is forced downward uponthe valve seat d as herein'before stated.

6 is a screw fitting into plug E. Screw 6 coming against theshoulder ein the shell or casing D renders it impossible to remove the plug E fromthe shell or casing.

F, is a stuffi-n'g box; and f, is the stuffing by means of which theescape of steam or water from the joint formed by the insertion of theplug E in shell or caseD is prevented.

At the upper end of the plug E there is secured on such plug, or formingan integral part thereof, the milled wheel E. 6 is a slot in such milledwheel E, and E is a receptacle at the upper end thereof into which mayplug being held in position by the nut G. In the fusible plug G there isplaced the pin g. Pin 9 may form an integral part of the fusible plug'Gand has been so constructed by me. 1

G ,v is a projecting lug extending beyond the upper face of the milledwheel E.

H, is a portion of the casing of the device removable therefrom when nofusible plug is contained in the device, but not removable therefromwhen a fusible plug is in place in such device.

The portion or part 1-1 of the shell or casing of thedevic'e hastl1erein,hole or passageway h, which fits upon the upper face of themilled wheel E. Projection II extends through the slot 6 in milled wheelE and has thereon abutment h extending underneath such milled wheel. Theabutment h is sufficiently large, in the dimension thereof parallel withthe axis of the plug E, that when such part H of the casing is slid intoposition on the milled wheel E such plug E cannot be turned down (bymeans of the screw threads thereon), so asto close the valve formed bythe lower end of such plug E fitting on valve seat d,- and hence whenthe part H is in position as illustrated in Fig. 4, an open passage-waywould extend through the shell or casing D, plug E extends.

- and the part H inserted in position. 1 vice is then again read-y foroperation. be placed the fusible plug G, such fusible and part H, (bymeans-of hole or passage-way kg) were it not for the fusible plug G, andso when water falls below the bottom of the tube or flue Gin the boiler,steam entering the tube or line C can and will extend to the plug G,

.andsuch plug G being composed of fusible metal, it will be fusedthereby and the steam will then escape through the plug.

In order to prevent the removal of the part H from the position in whichit is illustrated in Figs. 1, 2' and 4, the spring I is secured to theunder side thereof, in the chamber 72. in

such part I-I, and in the spring I there is the hole '5 into which thepin Gin the fusible-plug By means of this spring I, when the fusibleplug G is in proper position and the part H is slid .over it,.the pinwill engage with the spring I, and the part H will be thereby held inplace. hereinbefore stated, the valve formed by the lower end of theplug E fitting on the valve 7 d, cannot be closed. WVhen, however, the

When in place, as

fusible plug G, has been removed by melting or fusing, the part H can beslid off the milled wheel E and the valve closed; and this should bedone by the person in charge to prevent the continuous escape of steamfrom the safety plug after warning has been given by the device. Whenthe valve formed by the lower end of the plug E, fitting into thevalve-seat d has been closed as last above described, the part 1-1having been previously removed, the nut G can beremoved and a new plugG, fitted into proper position in the opening therefor,-E the plug Eagain raised,

The do- In the modification illustrated in Fig. 5, the casing iscomposed of a single shell havin g therein a valve and a receptacle inwhich the fusible pliug may be inserted and thepart H of such shell orcasing contained in the construction illustrated in Figs. 1 to 4,allinelusive, is omitted.

In the construction illustrated in Fig; 5, J,

is the shell or casing, J, is the valve-seat therein. K, is a valveadapted to fit on valveseat J. K, is thestuffing' box. L, is agroove invalve K. M, is a stop yieldingly held out of engagement with slot orgroove L in valve K byspring m when the fusible plug G,-isnot in placein thedevice, but forced into engagement with such groove by such plugwhen the plugis in proper position as illustrated in Fig. 5. N,is apassageway for steam or water extending from the valve-seat J in theshell or casing J, through such shell or casing; such passageway N beingclosed by the fusible plug G, and such passage-way performing the samefunctions as the passage-way e in hollow plug E, in the constructionillustrated in Figs. 1, to 4:, all inclusive. nut fitting into thecasing. J and havinglscrew threads thereon by means of Which-it can beforced down upon the fusible plug .G, thereby :holdi-ng such fusibleplug in placeflln the fusible plug-G, as such plugis-constructed IIO G,is the hollow for use in the construction illustrated in Fig. 5, thereis placed a groove g and in the easing J there is placed a spring I,which is adapted to engage with the groove g and thereby lock the plugin place.

In the modification illustrated in Fig. 6, the casing J is constructedsubstantially the same as in the construction illustrated in Fig. 5, thedifference in such construction consisting of the omission of the plugM, spring m, and groove L, and the placing of the fusible plug Gr sothat the stem 9 of the plug shall form a stop interposed between thevalve K and the valve-seat J.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a low water alarm the combination of a casing adapted to besecured to the shell of a steam boiler with a fusible plug, a valve inthe casing between the fusible plug and the boiler, and a keyless lockautomatically engaging with the fusible plug and preventing its removalfrom the casing except by fusing; substantially as described.

2. In a low water alarm the combination of a casing adapted to besecured to the shell of a steam boiler with a fusible plug, a valve inthe casing between the fusible plug and the boiler, a keyless lockautomatically engaging with the fusible plug and preventing its removalfrom the casing except by fusing, and a stop preventing the closing ofthe valve when the fusible plug is locked in position in the casing;substantially as described.

3. In a safety plug, the combination of a casing adapted to be securedto the shell of a steam boiler with a fusible plug, a passagewayextendingthrough such casing closed by the fusible plug, a valve in thecasing between the fusible plug and the boiler adapted to close suchpassage-way, a keyless lock automatically engaging with the fusible plugand preventing its removal from the casing except by fusing and a stopengaging with and preventing the closing of the valve when the fusibleplug is in position in the casing; whereby when the passage-way isclosed by the fusible plug, such passage-way cannot be closed by thevalve, and when such passageway is not closed by the fusible plug, itcan be closed by the valve; substantially as described.

4. In a safety plug the combination of a two part casing, one partthereof adapted to be secured to the shell of a steam boiler, a

passage-way through such part of the casing, a hollow plug fitting intosuch passage-way and adapted to form a valve closing the same, and afusible plug fitting into and adapted to close the opening through thehollow plug, and the other part of such casing adapted to be placed overthe hollow plug and when placed thereon to form a cover for such fusibleplug and also to form a stop preventing the closing of the valve formedby the hollow plug; substantially as described.

5. In a safety plug the combination of a two part casing, one partthereof adapted to be secured to the shell of a steam boiler, a

passage-way through such part of the casing, a hollow plug fitting intosuch passage-wayand adapted to form a valve closing the same, and afusible plug fitting into and adapted to close the opening through thehollow plug,

and the other part of such casing adapted to be placed over thehollowplug, and when so placed thereon to form a cover for the fusibleplug and a stop preventing the closing of the valve formed by the hollowplug, and a spring in such part of the casing adapted to engage with thefusible plug and thereby lock it in position as such cover and stop;substantially as described.

CLARENCE E. VAN AUKEN. Witnesses:

FLORA L. BROWN, PAUL 0. WEHRMAN.

